Resolving SIMOTION D425 Project Upload Failure in SCOUT V5

Field engineers commissioning SIMOTION D425 motion controllers frequently encounter a situation where SCOUT V5 (SIMOTION SCOUT) refuses to upload the complete engineering project. The target is reachable, communication is healthy, yet only the integrated SINAMICS S120 drive data is returned. The SIMOTION program source, the technology objects, the TO configuration, and the user data remain inaccessible on the engineering PG. This article documents the root cause, the corrective procedure, and the verification steps required to recover a complete project from a SIMOTION D425 running firmware V4.1 with SCOUT V5.2.1 over the X130 service interface.

1. Problem Statement: Partial Project Upload

The reported symptom is consistent across multiple service calls:

• The D425 controller boots normally, RUN/STOP LEDs are green, and the X130 port responds to ping and to the SCOUT "Accessible nodes" browse.
• SCOUT V5.2.1 establishes an online connection to the D425.
• The user selects Target system > Load to PG / Upload (also reachable as Project > Upload to PG in newer SCOUT builds).
• Only the SINAMICS Integrated drive object is brought back to the engineering station.
• The SIMOTION user program, the technology packages configuration, the axis configuration, and the cam data are missing from the resulting offline project.

Without these artifacts, the engineer cannot rebuild the offline project, cannot diff the running program against a known-good baseline, and most importantly cannot safely update the SIMOTION firmware on the D425 module because the source project that justifies the upgrade path is no longer available.

2. SIMOTION D425 Architecture and Project Storage

The SIMOTION D425 is a drive-based motion controller in the SIMOTION D family. It pairs a SIMOTION runtime (motion control, PLC, technology) with a SINAMICS S120 drive line-up on a single hardware platform. The relevant components for upload behaviour are:

The SIMOTION-side and SINAMICS-side data are stored in different partitions and managed by different upload mechanisms. SCOUT splits the upload into two independent transactions:

1. SINAMICS upload — reads the drive parameter image directly from the integrated SINAMICS. This transaction is always available because drive parameter data is part of the SINAMICS firmware state.
2. SIMOTION backtransfer — reads the offline project archive that was written to the SIMOTION file system at the time of the last download.

The second transaction depends entirely on whether an offline project archive was placed on the target during the last download. This is controlled by a single SCOUT download option.

3. Root Cause: Backtransfer Flag Not Persisted

SCOUT provides a download dialog box with several persistence options. The option that controls project backtransfer is named "Store additional data on the target" (German: "Zusätzliche Daten auf dem Ziel ablegen"). When this option is enabled, SCOUT writes a compressed offline project archive into the SIMOTION file system alongside the user program. The archive contains every source file required to reconstruct the offline project:

• ST, MCC, LAD/FBD source files
• Technology object configuration (axis, cam, output cam, measuring input, following object)
• User Data Unit (UDT) assignments
• Hardware configuration (HW Config export)
• Technology package selection set
• Version identifiers of all loaded components

If the checkbox is not ticked at the time of download, SCOUT writes only the runtime artefacts (compiled code, TO configuration in binary form) but no source archive. The SIMOTION runtime is fully functional, but a backtransfer cannot reconstruct the offline project because the source data was never placed on the controller.

This is precisely the situation reported in the original case: the controller is running a D425 V4.1 firmware with a valid project, but the engineering station that performed the last download disabled "Store additional data on the target". When the engineer later connected SCOUT V5.2.1 over the X130 service port, only the SINAMICS portion of the project could be recovered.

4. Preconditions for a Successful SCOUT Upload

Before attempting the corrective procedure, verify that the following conditions are met. Each item is a documented requirement of the SCOUT V5.2.1 online interface to a SIMOTION D425.

4.1 Hardware and connectivity

• The PG/PC is connected to the X130 service port of the D425 using a standard Ethernet cable (cross-over is not required on modern NICs but works).
• The PG/PC IP address is in the same subnet as the D425 X130 default address (169.254.11.22 is the as-delivered default on many D425 variants; check the unit label if the default has been changed).
• The D425 CF card is present, recognised, and not write-protected.

4.2 SCOUT installation

• SCOUT V5.2.1 (or a newer V5.x) is installed on the engineering station.
• The matching SIMOTION D425 V4.1 device support package is installed (typically installed alongside SCOUT).
• The correct technology packages are installed on the engineering station for the TPs used in the running project.

4.3 Project and authorization

• A SCOUT project exists, even if empty — SCOUT requires a project to be open in order to perform an upload to PG.
• The user has write permission on the project directory.
• If the project is password-protected at the source level, the password must be known before SCOUT will accept the uploaded source archive.

5. Step-by-Step: Enabling Backtransfer on a Re-Download

The corrective procedure replaces the controller-resident offline project archive with one that has the backtransfer flag set. The runtime behaviour of the running machine is preserved because the download only adds the archive; it does not modify the compiled user program unless the engineer explicitly re-compiles and re-loads.

Step 1 — Open the existing offline project

Open the most recent offline copy of the project in SCOUT V5.2.1. If no offline copy exists, the engineer must work with whatever SINAMICS data could be uploaded and rebuild the SIMOTION program by hand — see section 7.

Step 2 — Establish the online connection

1. Right-click the D425 node in the project tree.
2. Select Connect to target system.
3. Choose the correct Ethernet interface (the PG/PC interface that is physically patched to X130).
4. Confirm the dialog. SCOUT now displays the controller in Online state.

Step 3 — Open the Download dialog with backtransfer enabled

1. Right-click the D425 node.
2. Select Target system > Download (or Download to target system in some menu revisions).
3. The Download dialog opens. Locate the option "Store additional data on the target".
4. Tick the checkbox.
5. Click OK to start the download.

Step 4 — Verify the download completes

SCOUT displays a progress window for the download. Wait for the Download completed confirmation. The controller briefly enters Stop state and returns to Run once SCOUT issues the start command at the end of the download.

Step 5 — Disconnect and re-attempt the upload

1. Disconnect from the target system.
2. Reconnect to the target system to refresh the controller's view of the new archive.
3. Right-click the D425 node and select Target system > Load to PG / Upload.
4. SCOUT now uploads the SIMOTION portion and the SINAMICS portion. The offline project on the PG is rebuilt.

6. Alternative: Firmware Update Without Project Source

If the engineer is in a situation where the offline project cannot be reloaded (for example the original project is lost and the controller was last loaded by a different engineering team), the firmware update can still proceed, but with a constrained workflow. Only the firmware file and the SINAMICS parameters are guaranteed to be available; the SIMOTION user program and TO configuration must be backed up through other means.

6.1 What can be extracted from a SINAMICS-only upload

• Drive parameter set for SINAMICS Integrated (all DO types currently configured).
• DRIVE-CLiQ topology.
• Motor and encoder data, if they were entered as drive parameters.
• Setpoint channel configuration (p-series parameters).

6.2 What cannot be recovered from a SINAMICS-only upload

• ST / MCC / LAD/FBD source code of the SIMOTION user program.
• TO configuration values that are stored in the SIMOTION-side (axis limits, cam profiles, output cam tables).
• Technology package assignments and TP versions.
• Project-level version identifiers, library references, and compiler settings.

In this case, the engineer should follow the documented "Firmware update without project backup" procedure in the SIMOTION D425 commissioning manual. The procedure is provided as an annex because it is a sanctioned recovery path for cases where backtransfer is not possible. The procedure typically covers how to update the D425 firmware, how to perform a SIMOTION memory reset, and how to reload the runtime image from a separately archived "image file" backup of the CF card.

7. Recovering Project Source from SINAMICS-Only Upload

When only SINAMICS data has been uploaded, the SIMOTION program must be reconstructed manually. The workflow is outlined for completeness; in practice, it is always preferable to obtain the original offline project from a backup before attempting this.

7.1 Reconstruct the hardware configuration

1. Create a new SCOUT project with the correct D425 type (DP or DP/PN variant) and firmware version.
2. Open HW Config and add the D425 with the correct order number (for example 6AU1425-* for the D425 family; the exact MLFB is printed on the front panel of the unit).
3. Add the SINAMICS S120 line modules and motor modules that match the topology that was uploaded.

7.2 Re-create the technology objects

Open the axis configuration dialog and add TO types matching the SINAMICS drive data:

7.3 Recreate the program

Use the ST / MCC / LAD/FBD editors to rebuild the application logic. Cross-reference the SINAMICS parameters that were uploaded to identify which process data words are being used (e.g. telegram type 3, 5, 102, 105, 106) so that the SIMOTION program can address the correct I/O areas.

This recovery path is labour-intensive and error-prone. Use it only as a last resort and verify the result against the running machine before the machine is handed back to production.

8. Configuring the X130 Service Interface

The X130 port on the SIMOTION D425 is the standard engineering interface. It accepts standard Ethernet frames and uses the SIMOTION RPC protocol on top of UDP. Configuration is normally automatic once the PG and the controller are in the same subnet, but field engineers occasionally need to check or override the addressing.

8.1 Default addressing on the D425

8.2 Reading the actual X130 configuration

If the controller has been commissioned into a different network, the X130 IP may have been changed. The fastest way to discover it is from SCOUT itself:

1. Open SCOUT and select Online > Accessible nodes.
2. SCOUT broadcasts a discovery frame and lists every SIMOTION / SINAMICS node that responds, with its current IP.
3. Double-click the discovered D425 to open an online-only view of the controller.

8.3 When X130 cannot be reached

If "Accessible nodes" returns no D425, the field engineer should verify:

• Physical link LEDs on the X130 RJ45 socket are lit on both ends.
• No managed switch in the path is blocking the discovery multicast or the RPC UDP port (default UDP 17459, UDP 17460).
• Firewall on the PG/PC is not blocking the SCOUT discovery port.
• PG/PC has an interface in the same subnet as the controller (for the default, configure 169.254.11.1 / 255.255.0.0 on the PG temporarily).

9. SCOUT Version Compatibility Matrix

The D425 V4.1 firmware is compatible with a specific range of SCOUT V5 versions. The matrix below captures the supported combinations as documented in the SIMOTION SCOUT readme and the SIMOTION D425 firmware release notes. Always check the readme of the installed SCOUT for the exact list of supported firmware versions before upgrading.

10. Verification and Commissioning Checks

After performing the corrective download with the backtransfer flag enabled, the engineer should run through the following verification checklist before declaring the case closed.

10.1 Project integrity checks on the PG

• The uploaded project contains the SIMOTION user program in the expected source language (ST / MCC / LAD/FBD).
• The technology object count matches the count that was visible on the target before the download.
• The cam data, output cam data, and following object configuration are present.
• The technology package assignments in the project match those on the target (right-click D425 > Properties > Technology packages).

10.2 Online / offline diff

1. Connect online to the controller.
2. Right-click the D425 and select Compare online / offline.
3. Confirm the dialog shows "online and offline are identical" or, if the engineer re-compiled, only the expected compiler-stamp differences.

10.3 Backtransfer file presence on the controller

For the on-target backtransfer archive, the field engineer can use an FTP or a Windows share connection to the SIMOTION file system (the user must be configured in the SIMOTION user management with the right to access the file system). The archive is located under:

The exact file name and path depend on the SCOUT version and the project structure. The presence of any file in the USER partition under the project name is a positive indicator that backtransfer is enabled. An empty partition is the strongest indicator that the previous download did not enable the option.

10.4 Function test

Run the machine through one or two dry cycles to confirm that the upload-and-reload cycle did not disturb the production programme. Pay particular attention to:

• Axis homing sequences — homing offset is stored in the TO and must survive the reload.
• Cam switching — cam profiles and lead/lag values are stored in the TO and must be intact.
• Process data exchange — telegram types and slot assignments must match what the connected SINAMICS expects.

11. Common Pitfalls and Field Notes

The following items are the most common field pitfalls observed on SIMOTION D425 upload / firmware update jobs.

11.1 "Store additional data" resets at every SCOUT start

The checkbox state is not persistent across SCOUT sessions. The default at startup is unchecked. Every download must be reviewed.

11.2 Re-download overwrites the controller archive

If the original project is no longer available, performing a fresh download to the controller with a different offline project will overwrite the on-target archive. The original can no longer be recovered from the controller. Always archive the on-target archive (e.g. via FTP to a known location) before performing any download that is not strictly identical to the current controller state.

11.3 CF card swap changes the project signature

Replacing the CF card of a D425 (for example to upgrade to a higher-capacity card) writes a new on-target archive, but SCOUT will only backtransfer a coherent archive. A half-written archive from an interrupted card swap will fail the upload. Always perform a clean card format and a full download after a card swap.

11.4 Project password on the source archive

If the project is protected by a source-level password, the upload to PG will not work without the password. SCOUT will prompt for the password as soon as the backtransfer file is read. The password is part of the source archive and is set at project creation, not at download.

11.5 Knowledge — Siemens Industry Online Support

For firmware compatibility, project recovery procedures, and CF card handling, the Siemens Industry Online Support portal hosts the SIMOTION D425 manual set, the SCOUT readme, and the technology package release notes. Search the portal with the order number printed on the front panel of the D425 (for example 6AU1425-...) to find the matching documentation.

11.6 Standard references

For machine builders who must demonstrate that the upload / firmware update path is safe, the following standards provide the framework. They do not specify SIMOTION-specific procedures, so they should be read alongside the Siemens manuals:

• IEC 61131-3 — Programmable controllers, part 3: programming languages. Defines the source-level concepts that the SIMOTION source archive protects.
• IEC 61508 / IEC 62061 — Functional safety of electrical / electronic / programmable electronic safety-related systems. Relevant if the machine has safety functions that are loaded together with the user programme.
• ISO 13849-1 — Safety of machinery — Safety-related parts of control systems. Same caveat.

12. Summary Flow

The decision flow below summarises the diagnostic path that the field engineer should follow on a SIMOTION D425 upload that returns only SINAMICS data.

FAQ